Linux is a freely distributed open source operating system based on Unix. It was developed in 1991 by Linus Torvalds and has gained popularity as a free alternative to proprietary operating systems. There are several popular Linux distributions including Red Hat Linux, Linux Mandrake, Debian/GNU, and SuSE Linux. These distributions bundle Linux with common software like the X Window System, KDE, and GNOME desktop environments. Hardware compatibility has improved with Linux supporting many modern components, though some proprietary drivers may still be needed.